(a) Field of the Invention
The present invention relates to a field emission display and a method of fabricating the same and, more particularly, to a field emission display which effectively enhances electron emitting characteristics.
(b) Description of the Related Art
Generally, field emission displays (FEDs) are display devices where electrons are liberated from an emitter on a cathode by quantum mechanical tunneling and impinge upon phosphors on an anode, thereby producing a predetermined screen image.
A tip-based emitter and a broad area emitter may be used for such an emitter. The tip-based emitter is provided with a gate electrode, and electrons are emitted from the tip-based emitter due to differences in the applied voltages to the cathode and the gate electrode. In contrast, the broad area emitter does not have such a gate electrode, and electrons are emitted from the broad area emitter due to differences in the applied voltages to the cathode and the anode.
The tip-based emitter is prepared by forming an insulating layer and a gate electrode on the cathode, etching the insulating layer and the gate electrode, and depositing an electron emitting material such as molybdenum and silicon onto the etched space. The resulting tip-based emitter is provided with a large number of micro-tips corresponding to pixels.
However, due to the micro-tip structure of the tip-based emitter, it becomes difficult to uniformly form electron emitting tips over the entire display area and to employ the tip-based emitter for use in large area display devices. Furthermore, such a tip-based emitter is vulnerable to damage and necessarily involves extremely sophisticated tip formation techniques, resulting in increased production cost.
Alternatively, it has been suggested that a broad area emitter, using diamond, diamond-like carbon, graphite particles or carbon fibers, could replace the tip-based emitter with improved electron emitting characteristics.
Particularly, it is known that the carbon fiber-based emitter has a relatively good electron emitting characteristic. Such a carbon fiber-based emitter is usually prepared by cutting and pulverizing carbon fibers to make a carbon fiber powder, adding a frit and a binder to the carbon fiber powder to make an emitter paste, and printing the emitter paste onto a cathode. However, it turns out that the carbon fiber components are non-uniformly distributed over the display area. Such a non-uniform distribution of the carbon fiber components makes it difficult to obtain the desired electron emitting effect. This is presumably because the pointed end portion of the carbon fiber has a locally intensified electron emitting property and, due to the non-uniform distribution of the carbon fiber components, the pointed end portion of the carbon fiber cannot be directed toward the display screen.
This problem is also present in the graphite powder-based emitter where plate-shaped graphite particles are disorderly over-layered.
It is an object of the present invention to provide a field emission display which can effectively enhance electron emitting characteristics with an emitter having uniformly aligned electron emitting components.
These and other objects may be achieved by a field emission display including first and second substrates spaced apart from each other at a predetermined distance. The first substrate has a top surface, and the second substrate has a bottom surface. The top surface of the first substrate faces the bottom surface of the second substrate. A cathode is disposed on the top surface of the first substrate. The cathode has a top surface and a bottom surface. The bottom surface of the cathode contacts the top surface of the first substrate. An anode is disposed on the bottom surface of the second substrate. The anode has a top surface and a bottom surface. The top surface of the anode contacts the bottom surface of the second substrate. A phosphor screen is formed on the bottom surface of the anode. An emitter is formed on the top surface of the cathode. The emitter faces the phosphor screen.
The emitter includes an electron emission member having a longitudinal dimension, and an alignment member for aligning the electron emission member. The alignment member is formed with a magnetic material. The electron emission member is aligned by the alignment member such that the longitudinal dimension of the electron emission member is vertically extended from the cathode toward the phosphor screen of the anode.
The electron emission member may be formed with carbon fibers or graphite particles. The magnetic material is coated on the carbon fibers or graphite particles. Alternatively, the magnetic material may be incorporated into the internal structure of the carbon fibers or graphite particles.
A method of fabricating the field emission display includes the steps of 1) forming a cathode and an anode each through depositing a conductive layer onto a suitable substrate, 2) preparing an emitter paste through mixing an electron emitting material, a magnetic material and additives such as a frit and a binder, 3) screen-printing the emitter paste onto the cathode, 4) aligning the electron emitting material by forming a magnetic field in the vicinity of the printed emitter paste such that the electron emitting material can be arranged substantially vertical to the cathode, 5) solidifying the emitter paste by drying and burning it, and 6) sealing the substrates into one body.